<template>
  <div class="spec-preview">
    <img :src="image"/>
    <div class="event" @mousemove="handler"></div>
    <div class="big">
      <img :src="image" ref="bigImg"/>
    </div>
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script setup lang="ts">
import {ref} from "vue";

defineProps<{
  image: any
}>();
//mask元素
const mask = ref()
const bigImg = ref()

/**
 * 鼠标移动事件处理
 * @param event
 */
function handler(event: MouseEvent) {
  let left = event.offsetX - mask.value.offsetWidth / 2
  let top = event.offsetY - mask.value.offsetHeight / 2
  left <= 0 && (left = 0);
  top <= 0 && (top = 0);
  left > mask.value.offsetWidth && (left = mask.value.offsetWidth)
  top > mask.value.offsetHeight && (top = mask.value.offsetHeight)
  //设置遮罩的位置
  mask.value.style.left = left + 'px';
  mask.value.style.top = top + 'px';
  //设置大图的位置
  bigImg.value.style.top = -2 * top + 'px';
  bigImg.value.style.left = -2 * left + 'px';
}
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;
  box-sizing: border-box;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>
